(1) Field of the Invention
The invention relates to a method of operating an automatic door installation comprising door sensor equipment for conducting an obstacle check, in which method the automatic door installation is operable in a standard mode or a contingency mode depending on an operating condition of the automatic door installation.
(2) Description of Related Art Including Information Disclosed Under 37 C.F.R. §1.97 and 1.98
Automatic door installations, such as entrance doors for a building and elevator installations are provided with a number of sensors to ensure safe operation of the door installation, in particular the closing of the doors. For example, an elevator car of an elevator installation is typically provided with a door sensor for detecting the presence of an obstacle, such as a person or an object, in front of or between the elevator car doors. For example, the door sensor may be an optical door sensor, such as a break beam sensor, that forms a light curtain of infrared light outside of the elevator car doors (i.e. between the elevator car doors and the shaft doors when the elevator car is at a stop). The optical door sensor typically determines that there may be an obstacle in front of the elevator car doors when an emitted light signal is not detected by a receiver.
The operation of such an automatic door installation depends on whether the door sensor determines the presence of an obstacle or not. In the example of an elevator installation, confirmation that no obstacle is present is typically required before an elevator car can begin to move, and the doors may be prevented from closing if the door sensor determines that an obstacle is present. Accordingly, the door sensor can essentially cause the elevator installation to be taken out of service if it incorrectly determines that an obstacle is present, thereby preventing access to a building or other facility. Similarly, entrance doors will only open if an obstacle is determined to be present, and may not close whilst an obstacle is determined to be present. Access to a building or other facility can therefore be limited if the door sensor fails to correctly determine the presence of an obstacle.
The performance of the door sensor can depend on the operating conditions of the automatic door installation. For example, the performance of the door sensor can be affected by, amongst other things, optical and/or electronic noise and the temperature of the door sensor equipment. Deterioration of these and other operating conditions of the automatic door installation can prevent the door sensor from functioning normally, which may cause it to incorrectly determine that an obstacle is present. Accordingly, deterioration of the operating conditions of the automatic door installation can ultimately cause it to be temporarily taken out of service.
It is therefore desirable to provide an improved automatic door installation which is less prone to being taken out of service and can continue to operate despite deterioration of its operating conditions.